The objective of these studies is to determine the effects of physical stresses on the blood. We have evaluated the effects of physical stresses on the deformability of erythrocytes including the influence of metabolic changes on deformability. We are continuing studies with regard to the viscoelastic properties of clots and are evaluating the effects of physical stresses on white blood cells with regard to their functional properties. We are also investigating the influences of such stresses on platelets with regard to induction of aggregation and the influence of platelets on the viscoelastic properties of clots.